Yesterday, I read Elder Ballard's talk “Learning the Lessons of the Past,” Ensign, May 2009, 31–34.
This morning I read on Mormanity a topic that deals with the same idea ... learning from the past.
What I find interesting is that the pattern Elder Ballard describes (righteousness followed by prosperity, followed by material comforts, followed by greed, followed by pride, followed by wickedness and a collapse of morality until the people brought calamities upon themselves sufficient to stir them up to humility, repentance, and change) happened not only to the Nephites but other great civilizations we read about in history books. It seems that the Book of Mormon not only is "another testament of Jesus Christ" but it can also be another testament of the pattern of living righteously and wickedly followed by consequences.
Right now I'm reading a book about the 30 year Pelloponnesian War and what is shocking is learning that the sons who fought in this war (Sparta and her allies vs. Athens and her allies) are the grandsons of those men who fought together to defeat the Persians. How could two "countries" unite to defeat a common enemy and then in turn fight each other a few decades later? I think the answer is the same time and time again ... pride, wickedness, moral collapse, etc.